The present disclosure relates to a developing device that supplies developer to an image carrier and an electro-photographic image forming apparatus including the developing device.
In an electro-photographic image forming apparatus, an electrostatic latent image is formed by irradiating a circumferential surface of an image carrier (a photosensitive drum) with light based on information of an image read from a document image or based on information of an image transmitted from an external device such as a computer or the like. Toner is supplied from a developing device to the electrostatic latent image to form a toner image, which is then transferred onto a sheet. The sheet that has gone through the transfer process is then subjected to toner-image fixing processing, and discharged to outside.
In recent years, more and more complicated configurations have come to be adopted in image forming apparatuses along with progress in color printing and high-speed processing. In addition, for higher-speed processing, it is indispensable to achieve higher-speed rotation of a toner stirring member within the developing device. In particular, according to a development method in which a two-component developer containing magnetic carrier and toner is used, and in which a magnetic roller (a toner supplying roller) that carries the developer and a developing roller that carries only the toner are used, in an opposing portion where the developing roller and the magnetic roller face each other, a magnetic brush is formed on the magnetic roller, and by the magnetic brush, only the toner is carried on the developing roller, and further, the toner left unused for development is peeled off from the developing roller. This is liable to cause toner particles to float in the vicinity of the opposing portion where the developing roller and the magnetic roller face each other, and such floating toner particles accumulate around a trimming blade (a regulation blade). If the accumulated toner particles adhere to the developing roller in a condensed manner, they may eventually fall and cause an image defect.
As a solution to such a problem, for example, there is known a developing device in which a two-component developer containing magnetic carrier and toner is used, in which a magnetic roller that carries the developer and a developing roller that carries only the toner are used, and that further includes a toner receiver support member that faces the developing or magnetic roller, a toner receiver member that is disposed along a longitudinal direction of the toner receiver support member and receives toner fallen from the developing roller, and vibration generating means that vibrates the toner receiver member.
There is also known a developing device in which a sheet-shaped vibration adjusting member is disposed at both end parts of a toner receiver support member in its longitudinal direction to be spaced by a predetermined distance from a toner receiver member. In this developing device, when the toner receiver member vibrates, the toner receiver member comes into contact with the vibration adjusting member, whereby the toner receiver member is caused to vibrate in waves such that a free end of the toner receiver member moves warping in an arc, and thereby, toner accumulated on a free-end side of the toner receiver member is moved to a fulcrum side.